Atomically-precise dopant-controlled single cluster catalysis for electrochemical nitrogen reduction

The ability to precisely engineer the doping of sub-nanometer bimetallic clusters offers exciting opportunities for tailoring their catalytic performance with atomic accuracy. However, the fabrication of singly dispersed bimetallic cluster catalysts with atomic-level control of dopants has been a long-standing challenge. Herein, we report a strategy for the controllable synthesis of a precisely doped single cluster catalyst consisting of partially ligand-enveloped Au₄Pt₂ clusters supported on defective graphene. This creates a bimetal single cluster catalyst (Au₄Pt₂/G) with exceptional activity for electrochemical nitrogen (N₂) reduction. Our mechanistic study reveals that each N₂ molecule is activated in the confined region between cluster and graphene. The heteroatom dopant plays an indispensable role in the activation of N₂ via an enhanced back donation of electrons to the N₂ LUMO. Moreover, besides the heteroatom Pt, the catalytic performance of single cluster catalyst can be further tuned by using Pd in place of Pt as the dopant.